Liquid crystal monitors for image display are being used not only in offices or households but also at sites of various kinds of professional work, such as graphic design and medical care. In particular, high-end liquid crystal monitors are being used to display graphic design images or medical diagnostic images, since display of such images requires high-reproducibility, high-definition image quality. Further, high-end liquid crystal monitors that enhance the reproducibility of display images by measuring an optical property(s) of the liquid crystal screen, such as the luminance, chromaticity, or light quantity, using a photosensor and then performing monitor calibration on the basis of the measurement data obtained are currently commercially available.
A liquid crystal monitor consists of a liquid crystal display panel, a bezel surrounding the liquid crystal display panel, a backlight, electronic circuits, and the like. Currently, liquid crystal monitors including a sensor unit that performs monitor calibration using a photosensor are being commercialized.
Patent Literature 1 discloses a photosensor device: the photosensor device includes a body frame 102 disposed in a frame region around an image display panel, a photosensor used to measure the luminance, chromaticity, or the like of the image display panel, a sensor unit 113 containing the photosensor, a guide member that guides the sensor unit 113, and drive means that moves the sensor unit 113 to the measurement position; the sensor unit 113 is pushed out by the drive means and approaches a display screen 101 of the image display panel in such a manner to be guided by the guide member; and after a measurement, the sensor unit 113 is pulled back by the drive means so as to be stored in the frame 102 (FIG. 10).
Patent Literature 2 discloses a sensor unit actuation mechanism: the sensor unit actuation mechanism includes a frame disposed in a frame region around an object to be measured, a sensor unit on which a sensor for measuring a physical amount from the object to be measured is mounted, a guide member disposed in an x-direction to linearly move the sensor unit, a spring member that expands and contracts in a y-direction to return the sensor unit into the frame, and an actuator that expands and contracts in the y-direction to linearly move the sensor unit from within the frame to the measurement position in the x-direction; the x-direction and y-direction have a relationship where if the x-direction is the horizontal direction when the frame is seen from the front side, the y-direction is the vertical direction; and by energizing the actuator so that the actuator contracts against the resilience of the spring member, the sensor unit linearly moves from within the frame to the measurement position in the x-direction.
Patent Literature 3 discloses a flat display device: the flat display device includes a graphics processor; in calibration mode, the luminance of a white image displayed on a panel on the basis of an image signal corresponding to the maximum video level from an analog image signal is detected by a sensor disposed in a region that is not seen by the observer of the flat display; there is provided rotation means capable of rotating the sensor from the rest position to the luminance detection position approximately in parallel with the panel; and the graphics processor adjusts the gain in accordance with an change in the detected luminance, which is caused by a stepwise change in the gain by the graphics processor.